The present invention relates to an artificial key material, and more particularly relates to improvements in the workability and properties of a synthetic key material used for key board musical instruments such as pianos, organs and accordions.
As well known, natural ivory is well suited for keys or surface coverings of keys of keyboard musical instruments. In addition to the high price of the material, however, the recently growing international trend for protection of natural animals hinders the free and abundant use of ivory for these purposes. Ebony, which is also used to this end, is again very high in price and, moreover, its significant variation in quality and inevitable colour fading in use limit broader use of this material for keys. Out of such a background, the use of synthetic resins as a substitute for these natural materials has acquired an enlarged market.
Thermosetting resins such as phenol and urea as well as thermoplastic resins such as polymethyl methacrylate have been generally used for production of artificial keys. Use of the thermosetting resins, however, is inevitably accompanied by the problem of poor workability in production processes, whereas the sole use of the thermoplastic resins tends to cause undesirable slippage of players' fingers on the keys during performance due to the relatively low sweat absorption of the thermoplastic resins.